Speed up compares with characters ie single-character strings....

test/mjsunit/compare-character.js

+// Copyright 2008 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
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+//     * Redistributions in binary form must reproduce the above
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+//       with the distribution.
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+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
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+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Test the optimized implementation of comparison with single-character
+// strings.
+
+var a = ['', String.fromCharCode(0), ' ', 'e', 'erik', 'f', 'foo', 'g', 'goo',
+         -1, 0, 1, 1.2, -7.9, true, false, 'foo', '0', 'NaN' ];
+for (var i in a) {
+  var x = a[i];
+  var f = 'f';
+
+  assertEquals(x == f, x == 'f', "==" + x);
+  assertEquals(x === f, x === 'f', "===" + x);
+  assertEquals(x < f, x < 'f', "<" + x);
+  assertEquals(x <= f, x <= 'f', "<=" + x);
+  assertEquals(x > f, x > 'f', ">" + x);
+  assertEquals(x >= f, x >= 'f', ">=" + x);
+  assertEquals(f == x, 'f' == x, "==r" + x);
+  assertEquals(f === x, 'f' === x, "===r" + x);
+  assertEquals(f > x, 'f' > x, "<r" + x);
+  assertEquals(f >= x, 'f' >= x, "<=r" + x);
+  assertEquals(f < x, 'f' < x, ">r" + x);
+  assertEquals(f <= x, 'f' <= x, ">=r" + x);
+}
+